Fluorescent lamps having a strong UV output have been used for many years as a substitute for sun-tanning and in medical treatments for various skin disorders. It has often been difficult to determine when the effective UV output of the lamp has diminished beyond a useful function since the lamp may continue to emit visible radiation.
For example, the useful life of a fluorescent lamp is determined by the amount of UV radiation present at 500, 800 and 1000 hours, respectively. At the present time there exists no useful determinant of the available amount of UV radiation other than keeping track of the total number of hours the lamps have been illuminated, a troubling and often inaccurate procedure that depends, among other things, upon careful record keeping.
Accordingly, it would be an advance in the art if a determinant could be easily supplied with the lamp to indicate its useful life.